Slitting machine



y 1950 A. J. CASAGRANDE 2,506,343

SLITTING MACHINE Filed June 26, 1946 lag-'- Fig.5.

Fig.2. i

m INVENTOR.

A nThon J. Casagr-ande,

A TTQRNEY Patented May 2, 1950 SLITTIN G MACHINE Anthony J Casagrande, Schenectady, N. Y.', assignor to General Electric Company, a corporaon of New York Application June 26, 1946, Serial No. 679,430

4 Claims.

This invention relates to slitting machines and more particularly to improvements in machines for slitting very thin sheet or strip material into a plurality of narrower ribbons.

So-called gang slitting machines are well known in which a plurality of spaced cutter wheels on one shaft have their edges fitted between a similar group of cutter wheels on a parallel shaft. The two shafts rotate in .opposite directions and the material to be slit is fed between the rows of cutters where it is sheared between the sharp edges of adjacent cutter wheels. Heretofore, such machines have been provided with so-called strippers in the form of resilient wheels which are in between the cutter wheels andwhich serve to support the material to be slit, and these strippers have been fixed on their respective shafts in the same way that the cutters are. However, I have found that such machines do not slit very thin material as well as they do thicker material. By very thin material I mean material less than .001 inch thick. The prior art machines produce wrinkling and ragged edges on the strips when th material gets thinner than about .005 inch.

In accordance with this invention I have provided a machine in which wrinkling and ragged edges on the strips are eliminated and also curling and breaking of the strips is reduced to a minimum even when the thickness of the material is reduced to .0001 inch. This improved result is achieved by mounting the resilient strippers in a freely rotatable manner relative to the cutters so that the peripheral speed of the stripper face is automatically synchronized with the speed of the opposing cutter face, regardless of the amount of deflection in the resilient member of the stripper. In this manner any tendency toward unequal surface tension in the material being cut is eliminated.

An object of the invention is to provide a new and improved slitting machine.

Another object of the invention is to provide a machine for slitting material of less than .005

inch in thickness with the production of sub- 5 stantially no wrinkling or ragged edges on the slit material.

A further object of the invention is to provide a new and improved gang slitting machine for very thin material.

The invention will be better understood from the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

In the drawing Fi 1 is a plan view of an em- 55 thin facing ring 2|.

bodiment of the invention; Fig. 2 is a side elevation view of the machine shown in Fig. 1; Fig. 3 is an end view of the machine shown in Figs. 1' and 2; Fig. 4 is a sectional view on the line the boundary zone between contact and no contact of the surfaces of opposing cutters and strippers; Fig. 6 is a part sectional view taken at right angles to those shown in Figs. 4 and 5; Fig. '1 is an actual size photograph of two strips of aluminum foil .0003 inch thick which have been slit respectively on a conventional machine and on my machine; and Fig. 8 is a photograph of the adjoining edges of the strips shown in Fig. 7 when enlarged seven and one-half times.

Referring now to the drawing and more particularly to Figs. 1, 2, and 3, the machine is shown as comprising a base or bed plate I on which are mounted spaced upward by extending brackets 2 in which are journaled a pair of spaced parallel shafts or arbors 3 and I. The shaft 3 is driven in any suitable manner such as by a motor 5, through a worm gearing B, and a pair of equal size spur gears 1 on the opposite ends of the shafts cause shaft 4 to be driven at the same speed as shaft 3 but in the opposite direction. The brackets are rigidly braced by shouldered tie bolts 8.

Fixedly mounted on the shaft 3 are a, plurality of cutter wheels 9 which are preferably of equal diameter and are also preferably equally spaced apart. Likewise, fixedly mounted on the shaft 4 is another set of sharp edged cutter wheels 9 and it will be seen from Fig. 2 that the two sets of cutter wheels are offset or staggered so that the edges of the cutters on one shaft may be fitted between the edges of the cutters on the other shaft. The proper degree of interfitting or overlapping of the edges is readily adjustable by means of jack screws l0 threaded into the brackets 2 and bearing against journal supports l I for the shaft 4. As shown inost clearly in Fig. 3, the latter are attached to plates l2 which are attached to the brackets 2 by studs l3 passing through slots I4 which allow the required amount of vertical movement.

In Fig. 1 a strip l5 of material to be slit is being fed into the machine in the direction of the arrow and emerges slit into a plurality of ribbons l 6 on the other side of the machine.

For supporting the material fed into the machine and slit between the edges of the'cutters 9 are compound strippers I1. These are wheels which are located between the cutters 9 and which are freely rotatable on their respective shafts 3 and 4. As shown in Fig. 4, the strippers,

each of which is mounted on a spacer l8, comprise a backing ring i 9, a resilient bumper 20 and a The backing ring l9, resilient bumper 20, and facing ring H are preferably cemented together so that they rotate as a unit. The spacer l 8 is firmly held by the adjacent cutters and the backing ring I 9 has a sliding fit so H of Fig. 6 which passes through the centers .60 that it can rotate freely around the former. Fig.

3 4 shows how the parts are interfitted in the central plane of the machine which passes through the centers of the shafts 3 and 4 and the overlapping or fitting together of the edges of the cutters is clearly shown. This figure also clearly shows how this results in the shearin action which separates the strip I5 into ribbons I6. A

comparison of Figs. 4 and 5 shows how the resilient bumper rings are compressed along the center plane, as shown in Fig. 4, in comparison with their dimensions at points where the surfaces of the strippers and cutters are not in engagement.

The reason the strippers I! are freely rotatable on their respective arbors by means of relatively low friction sliding fits between the non-resilient members l8 and I9 is to make allowance for any difference in outer peripheral or circumferential length of the strippers I! and the cutters 9. It is exceedingly difficult as a practical matter to make the peripheries of these two elements exactly the same. If there is any differehce and if the strippers and the cutters are both fixedly mounted on their respective arbors, there will 'be a sliding 0r tearing action against the material being slit and in the case of very thin materials, which the present machine is intended to slit, this will cause injury and tearing and rough edges of the slit material as shown in the upper part of the photograph in Fig. 8. Furthermore, it is sometimes desirable to make the strippers ll of a larger diameter than the cutters 9, as shown in Fig. l, in order to secure more positive ejection of the slit material from between the adjacent cutter wheels and in that case the freely rotating mounting of the strippers permits them to rotate more slowly than the cutters so that the surface speeds of the two are the same as the surface speed of the strip being slit.

In Fig. '7 a full scale photograph of a ribbon of aluminum .0003 inch thick which has been slit on a conventional machine is shown at 22 and a ribbon of the same material which has been slit by my invention is shown at 23 and it will be observed that the ribbon 22 has a more wrinkled appearance than the ribbon 23.

In Fig. 8 the edges of the ribbons 22 and 23 have been enlarged seven and one-half times and the resulting magnification clearly shows the ragged edges of the strip 22 which was produced by a conventional machine in contrast with the relatively straight, smooth edge of the ribbon 23.

While there has been shown and described a particular embodiment of this invention, it will be obvious to those skilled in the art that various changes and modifications can be made therein without departing from the invention and therefore it is aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. A slitter for thin strip or sheet material comprising, in combination, a pair of cutting Wheels having overlapping edges for shearing material which passes between them, and a pair of radially resilient stripping wheels each of which is coaxially adjacent one of said cutting wheels and in peripheral contact with the other cutting wheel whereby said stripping wheels firmly support the material to be slit, each of said stripping wheels comprising an outer facing ring of larger diameter than its coaxially adjacent cutting wheel, an inner radially resilient ring and antifriction mounting means within said inner resilient ring. said stripping wheels being ro- 4 tatable freely relative to their respective coaxially adjacent cutting wheels.

2. A continuous slitter for thin strip or sheet material comprising, in combination, a pair of parallel shafts, means for rotating said shafts in opposite directions, a plurality of cutting wheels fixedly mounted respectively on said shafts, said cutting wheels being of suchdiameters that their peripheries overlap, adjacent sides of said wheels being in contact, and a plurality of stripping wheels freely rotatably mounted respectively on said shafts, each stripping wheel being adjacent a cutting wheel which is on its shaft and havin its periphery in contact with the periphery of a cuttin wheel which is on the other shaft, each stripping wheel comprisin an outer facing ring, an inner radially resilient bumper and anti-friction means within said resilient bumper for mounting said facing ring and said resilient bumper on said shaft, said stripping wheel having a larger diameter than said cutting wheel on its respective shaft.

3. A continuous slitter for thin strip or sheet material comprising, in combination, a pair of parallel shafts, means for rotating said shafts at the same angular speed in opposite directions, a plurality of square edged cutting wheels fixedly mounted respectively on said shafts, said cutting wheels being of equal diameter which is slightly greater than the spacing between the center lines of said shafts whereby the peripheries of said wheels overlap, adjacent sides of said wheels being in contact, and a plurality of stripping wheels freely rotatably mounted respectively on said shafts, each stripping wheel being adjacent a cutting wheel which is on its shaft and having its periphery in contact with the periphery of a cutting wheel which is on the other shaft, each stripping wheel comprising an outer facing ring, an inner radially resilient ring and anti-friction means within said resilient ring for mounting said ring on its respective shaft, said stripping wheels having a larger diameter than said cutting wheels.

4. A gang slitting machine for thin strip or sheet material comprising, in combination, a pair of parallel shafts, means for rotating one of said shafts, means for driving the other shaft at the same speed but in the opposite direction from the first shaft, a plurality of equal diameter cutting wheels fixedly mounted on each of said shafts, said cutting wheels being in staggered relation on the two shafts, means for adjusting the spacing between said shafts so as to interfit the peripheries of the cutting wheels on the two shafts, and compound stripping wheels on each shaft between said cutting wheels, said stripping wheels each comprising an outer facing ring of slightly larger diameter than said cutting wheels, an inner resilient ring, and a backing ring within said resilient ring, said stripping wlhefils being relatively rotatably mounted on said s a ANTHONY J. CASAGRANDE.

REFERENCES CITED 'The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 394,201 Merritt Dec. 11, 1888 474,822 Foote May 17, 1892 1,273,228 Humiston July 23, 1918 Deck Sept. 29, 1931 

